David Starr, Space Ranger, like all the books in the Lucky Starr series, sets good against evil. As in many adult space operas, the characters fall into three distinct groups: the major heroes (David Starr, the Council of Science, Bigman Jones), the local "good guys," and the "bad guys" (one principal villain and some unpleasant bullies).

In this book, Asimov introduces two characters who recur throughout the Lucky Starr series, David Starr and Bigman Jones. David Starr, youngest-ever member of the Council of Science, is the sole survivor of an expedition to Venus during which pirates killed his parents.

Tall, athletic, and brilliant, he has carried on his father's career with the help of his father's old friends, Hector Conway and Gus Henree. John "Bigman" Jones, a scrappy, stubborn Martian farmboy who stands barely five foot two, has run afoul of some influential people...